The invention relates to a multiple crank drive for working machines, in particular for diaphragm pumps.
This class of prior art multiple crank drive, which is used to drive several working machines, which are arranged side by side and are connected together, in particular, for example, for so called triplex diaphragm pumps, is usually designed in such a manner that there is a common crankshaft, on which the individual crank drives, usually comprising eccentric, connecting rod, connecting rod head, etc., are spaced apart. The two ends of this crankshaft, which exhibits automatically a significant length owing to the working machines, arranged side by side, are disposed in a housing by means of a bearing. Owing to this automatically longer length of the crankshaft, it must also be relatively strong. That is, it is designed with an adequately large diameter. In addition, there is significant stress on the bearing, a feature that also necessitates correspondingly a bearing of large dimensions.
This stress is also increased due to the fact that the drive for the crankshaft, in particular a worm gear, is also mounted on the crankshaft and is usually located in the interior of the housing in the vicinity of an end-sided bearing of the crankshaft.
Therefore, the invention is based on the problem of designing this class of multiple crank drive so that the aforementioned drawbacks are remedied. To this end, the crankshaft is built shorter, can be provided with a smaller diameter and finally generates only lower stress on the bearing.
The invention is based on the important idea of suspending the crankshaft, serving to drive multiple working machines, in the housing. In a preferred embodiment of the invention this means that the bearing of the multiple crank drive is located exclusively on both sides of the central crank drive.
For this reason the crankshaft does not need any end sided pins, which served hitherto the mounting, so that the crankshaft can be built altogether shorter and thus can also be provided with a smaller diameter. The result is also the important advantage of less bearing stress, so that bearings with small dimensions can also be provided.
In a practical embodiment this means that in an otherwise identical configuration a crankshaft, which exhibited in the past a length of 2.10 meters, can be built with a length of 1.50 meters.
Another advantageous reduction in the length of the crankshaft results when, according to the invention, the drive for the multiple crank drive is disposed between two crank drives. Preferably the drive is also located in the vicinity of a bearing.
Thus, the invention achieves, on the whole, significant design advantages, which have in the final analysis a beneficial effect on the price structure of the entire arrangement.